/*
 * Copyright 2002-2016 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.core.annotation;

import org.springframework.lang.Nullable;
import org.springframework.util.ReflectionUtils;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;

/**
 * Default implementation of the {@link AnnotationAttributeExtractor} strategy
 * that is backed by an {@link Annotation}.
 *
 * @author Sam Brannen
 * @see Annotation
 * @see AliasFor
 * @see AbstractAliasAwareAnnotationAttributeExtractor
 * @see MapAnnotationAttributeExtractor
 * @see AnnotationUtils#synthesizeAnnotation
 * @since 4.2
 */
class DefaultAnnotationAttributeExtractor extends AbstractAliasAwareAnnotationAttributeExtractor<Annotation>
{

    /**
     * Construct a new {@code DefaultAnnotationAttributeExtractor}.
     *
     * @param annotation       the annotation to synthesize; never {@code null}
     * @param annotatedElement the element that is annotated with the supplied
     *                         annotation; may be {@code null} if unknown
     */
    DefaultAnnotationAttributeExtractor(Annotation annotation, @Nullable Object annotatedElement)
    {
        super(annotation.annotationType(), annotatedElement, annotation);
    }


    @Override
    @Nullable
    protected Object getRawAttributeValue(Method attributeMethod)
    {
        ReflectionUtils.makeAccessible(attributeMethod);
        return ReflectionUtils.invokeMethod(attributeMethod, getSource());
    }

    @Override
    @Nullable
    protected Object getRawAttributeValue(String attributeName)
    {
        Method attributeMethod = ReflectionUtils.findMethod(getAnnotationType(), attributeName);
        return (attributeMethod != null ? getRawAttributeValue(attributeMethod) : null);
    }

}
